Geological influence

These examples illustrate recent interest in investigating the potential of sulfur compound distributions for improving our understanding of geologic influences in determining variations in composition of crude oils with relation to source and evolution history. 

In Europe, the notion that it may be possible to determine a natural background concentration of a metal at most sites may be unrealistic. Many hundreds of years of industrial activity, urbanization, and widespread aerial deposition mean that it is best to consider background concentrations as those determined at sites of relatively low anthropogenic impact. These concentrations will still vary considerably from site to site due to geological influences. 

Thuro, K. 1997. Drillability prediction - geological influences in hard rock drill and blast tunnelling. Geol. Rundsch. 86, pp 426 - 437. 

However, the coalification process is snbject to local chemical and geological influences, and the type of coal formed, being snbject to these inflnences, is not consistent within any country or geological period. While it might be claimed that significant progress has been made in this area, the jury is still out leading to much speculation and the application of a plethora of characterization techniques. 

The final composition of stream water is the product of the weathering reactions and related processes outlined above. However, the chemical processes are influenced and controlled by an intricate combination of environmental factors that are characteristic for each drainage system. Therefore, the composition of the bedrock in an area and the residual material left at the surface as soil and subsoil exert a strong influence on the chemical composition of mnoff from the area. The reactions of water with this material are the ultimate geological control and are the source of soluble weathering products. 

Natural gas, found in geological accumulations, normally refers to the gaseous fossil-based equivalent of oil. Its composition varies widely, from high concentrations of nitrogen and carbon dioxide to (almost) pure methane. In general, it contains low concentrations of the higher (saturated) hydrocarbons, which influence the physical properties and may present condensation problems in high-pressure transport lines. 

Joly, J. (1909). R idio icdvity and Geology An Account of the Influence of Radioactive Energy on Tcircstrial TJistoiy. London A. Conscable. 

The Table shows a great spread in Kd-values even at the same location. This is due to the fact that the environmental conditions influence the partition of plutonium species between different valency states and complexes. For the different actinides, it is found that the Kd-values under otherwise identical conditions (e.g. for the uptake of plutonium on geologic materials or in organisms) decrease in the order Pu>Am>U>Np (15). Because neptunium is usually pentavalent, uranium hexavalent and americium trivalent, while plutonium in natural systems is mainly tetravalent, it is clear from the actinide homologue properties that the oxidation state of plutonium will affect the observed Kd-value. The oxidation state of plutonium depends on the redox potential (Eh-value) of the ground water and its content of oxidants or reductants. It is also found that natural ligands like C032- and fulvic acids, which complex plutonium (see next section), also influence the Kd-value. 

In developing and applying the erosional-depositional system, careful consideration was given to the environmental factors which influence the potential for erosion, transport and deposition climate, topography, geology and soils, as well as human activity. 

Watersheds, also known as drainage basins, define a natural context for the study of relationships among soils, geology, terrestrial ecosystems, and the hydrologic system because water and sediment travel downslope under the influence of gravity. This material is a continuation of some of what was presented in Chapter 6. 

Shikazono, N. and Shimizu, M. (1993) Tectonic influences on temporal and spatial relationships in the Kuroko-type and vein-type deposits in southwest Hokkaido metallogenic province, Japan. Resource Geology Special Issue, 15, 401-413. 

Raymo, M.E., Ruddiman, W.F. and Froelich, P.N. (1988) Influence of late Cenozoic mountain building on ocean geochemical cycles. Geology, 16, 649-653. 

US Department of the Interior, Pesticides in Surface Waters, Current Understanding of Distribution and Major Influences. Eact Sheet 039-97. US Geological Survey, Washington, DC (1997). 

Compliance with these requirements will be conditioned by the type of store and its area of influence. Clearly, monitoring techniques will be very different in stores on-shore and offshore, and within a storage type, geological, hydrological and even ecological characteristics will favour the implementation of a methodology or other. 

Polar and subtropical fronts have shifted southwards in the (geologically) recent past and many regions that are arid today once had a more humid climate. Conversely, many of the present humid regions were much drier in glacial periods, especially between 20,000 and 13,000 BP when aeolian processes influenced land formation more than at present. Mass wasting, fluvial processes and aeolian processes are the most important landform-shaping factors in arid and semi-arid regions. 

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